Improvement in projectiles for rifled ordnance



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B. B. HOTCHKISS, OF NEW YORK, N. Y.

IMPROVEMENT lN' PROJECTILES FOR RIFLED ORDNANCE.

Specification forming part ofLettcrs Patent No. $3,027, dated June 7, 1864.

T 0 all whom it may concern:

Be it known that l, B. B. HoToHKiss, of th: city, county, and State of New York, have invented a certain new and useful Improve merit in Itifled-Cannon Projectiles; and I do hereby declare that the followingis afull, clear, a id exact description of the same.

The accompanying drawings form a part of this specification.

Figure 1 is a longitudinal central section in the plane indicated by It R in Figs. 2, 3, and

4. Fig. 2 is a transverse section in the plane indicated by S S in Fig. 1. Fig. 3 is a corresponding section in the plane indicated by T T in Fig. 1. Fig. 4 is a corresponding section in the plane indicated by U U in Fig. 1. Fig. 5 is acorresponding section in the plane indicated by V V in Fig.1. All these figures show the condition of the parts before firing. Fig. (i is a transverse section in the plane indicated by U U in Fig.1,showing the condition of the parts after the projectile has been fired.

Similar letters of reference indicate like parts in all the drawings.

My invention is an improvement on what is known as the Hotchkiss projectile. Its object is to provide channels or passa ges through which the gases formed by the bnrnin g of the powder may flow, not only along the iron portions, but also along those portions of the channels which traverse the lead belt, and to avoid their becoming closed by the swaging of the lead in being fired. It is of great importance in the nsegot' such shells with timefuses to allow a portion of the gases or flame from the powder to pass to the front of the projectile to ignite the fuse; and in the use of such and all projectiles-as, for example,

percussion shells and solid projectilesit is desirable to allow a portion of the gases or flame to flow past the projectile, in order to moderate the violence with which the powder acts. 1 have demonstrated by experiment that the range and penetration of the projectile with an ordinary charge of powder is not din'iinished by providing passages arranged as I have here represented; but in case these should be diminished, under any circnin stances, it may be remedied by using a larger quantity of powder.

In order with more clearness to indicate by dotted lines the form of the parts which are beyond the plane of section in Fig. 1, I have represented my projectile as solid. I apply the invention in the same manner to timeshells and other shells as is here represented.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation, by the aid of the drawings and the letters of reference marked thereon.

A and B are the iron portions, and O the lead belt. The part B is adapted to fit over the part A, and to slide forward thereon in the act of being fired. The conical or wedgeshaped form of the forward portion, B, of the cap B, and the portion A of the part A are adapted to promote the expansion of the lead 0, and the grooves a and b cause the lead belt 0 to lock the parts A and B together. These parts, so far as yet described, correspond in general to the forms which have been shown in the patents previously issued to me, and are based on the invention patented to my brother, Andrew Hotchkiss, in 1855.

D D D are grooves extending longitudinally along the surface of the entire projectile. The portions which traverse the surfaces of A and of B are in line with the portions which traverse the lead belt 0. They may be arranged spirally. so as to correspond exactly or very nearly with the grooving of the cannon from which they are to be fired, if it is known what is the rate of twist of such cannon; but I do not deem this at all important. It may be preferable even to'arrange them spirally in an opposite direction, so as to stand across rather than parallel to the grooving of the cannon. In my experiments I have found them to succeed admirably with the grooves extending straight along the cylindrical surface of the projectile, as indicated in Fig. 1.

I apply mylead belt 0 by casting it in place. To do this I insert the parts A and B properly in a mold of iron. The general surface of the interior of this mold is cylindrical, but is provided with three internal ridges, corresponding to the grooves D D D.

No difficulty will be experienced by any good mechanic in inserting the parts A and B into the mold and removing the projectile therefrom after the lead is hardened. I remove a portion of the material of A and B at the points A B directly under each groove D D D. The form of these parts is very clearly shown in the drawings. It results on the projectile.

from the form of the parts A and B, as modified by a removal of the parts at A and B that the sliding forward of B upon A wedges out the lead belt by the conical surfaces A and B between the grooves D D D, but does not wedge out to the same extent, or scarcely at all, that portion of the lead which is under those grooves. The result is the maintenance ofthe channels with but a slightly-diminished area after the lead has been expanded. This result maybe more clearly understood by considering that the section of the lead belt 0 in the plane of either the channels D does not exhibit the wedge'like form which is presented by the section through any of the intermediate lines. The effect of the forward movement of 1) upon A is to disturb and swage the lead which lies in the space provided for the belt 0; but the parts immediately adjacent to the grooves D are not wedged outward alone, but are simply compressed and compelled to swell, with atendency to do so equally in all directions. Thelead intheintermediate spaces between the channels D is, on the contrary, wedged radially outward by the action of the conical surfaces A and B. It follows that the lead in the vicinity of each groove D is swelled only partly outward.. The other portion of its swelling is performed laterally. In other words, the lead along the grooves D D D is crushed with a slight tendency to expand radially, while the remainder of the lead is crushed with a much stronger tendency to expand radially. The efl'ect is the obvious one., The lead belt 0 is swelled or expanded radially to a marked extent between the grooves D, while the grooves D are not closed up or even diminished in area, except to a small extent.

I have referred to the material of the belt 0 as lead. In practice I prefer to form this soft packing of an alloy composed principally of lead, but with such additions of tin orother harder metal as will give it a proper degree of hardness. The hardness may vary within wide limits. The recesses A and B and the conical or wedge-like portions A and- B, which intervene between them, form, in eflect, a series of mutual projections and depressions in the iron and in the lead, which aid in preventing the lead belt from turning or slipping around The tendency thus to slip is ordinarily resisted with sufiicient force by the adhesion and friction of the parts; but on very large projectiles the mutual interlocking presented by these parts in this invention is of advantage in adding to resist such motion, v and to compel the entire projectile to rotate in strict accordance with the riding.

Anothrr important advantage due to my invention is that the belt or expansive material (3, notwithstanding the grooves D extend across it, is of uniform strength, or nearly so, throughout. belt 0 on the inner side to the same extent, or nearly so, that the groove D takes away the material from its outer side, and the construction is in this feature the same in efi'ect on the strength of the belt, as if a recess in the hard portions of the shot extended quite across under the belt, and the belt were, of course, correspondingly formed to fill them. In such case a cross section of the shot would exhibit a serpentine form of the belt G, and I propose to extend such recesses along the body in the manner here suggested, as extensions of the recesses A and B", if it shall ever prove desirable; but on all projectiles of moderate size, and constructed and proportioned as above represented, I prefer the form indicated in the drawings.

In case my invention is applied to projectiles intended to be used in breech-loading cannons, the above description applies equally well, except that I make thebeltO of alarger exterior diameter than the rigid portions A and B. In such cases, too, a smaller degree of motion of the part B upon the part A in the act of firing will obviously suifice to expand the packing (J, by reason of the fact that the expansive material C comes from the manufactory somewhat larger than the bore (or the diameter measured to the surface of the lands) of the gun.

Having now fully described my invention, what I claim as new therein, and desire to secure by Letters'Patent, is-

1. In rifle-cannon projectiles, the recesses A B in the rigid portion or portions, arranged relatively to grooves D on the exterior of the expansive packingO, as indicated, the recesses in the rigid material being arranged opposite or under the grooves in the expansive material, in the manner and for the purposes herein set forth.

,2. The within described form and arrangement of the parts A, A, A, B, B,B O, and D, whereby the recesses A I3 alternate between wedge like portions A B, near the front and rear edges of thebelt of soft matcrial, O, as and for the purpose specified.

In testimony whereof I have hereunto set my name in the presence of two subscribing witnesses.

B. B. HOTCHKISS. Witnesses:

THoMAs D. Srn'rson, H. A. ALBEE.

The recesses A B thicken the 

